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authorLinus Torvalds <torvalds@linux-foundation.org>2014-12-20 16:48:59 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-20 16:48:59 -0800
commit60815cf2e05057db5b78e398d9734c493560b11e (patch)
tree23d7f55df13cc5a0c072cc8a6f361f8e7050b825 /arch/s390/kvm/gaccess.c
parentbfc7249cc293deac8f2678b7ec3d2407b68c0a33 (diff)
parent5de72a2247ac05bde7c89039631b3d0c6186fafb (diff)
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux
Pull ACCESS_ONCE cleanup preparation from Christian Borntraeger: "kernel: Provide READ_ONCE and ASSIGN_ONCE As discussed on LKML http://marc.info/?i=54611D86.4040306%40de.ibm.com ACCESS_ONCE might fail with specific compilers for non-scalar accesses. Here is a set of patches to tackle that problem. The first patch introduce READ_ONCE and ASSIGN_ONCE. If the data structure is larger than the machine word size memcpy is used and a warning is emitted. The next patches fix up several in-tree users of ACCESS_ONCE on non-scalar types. This does not yet contain a patch that forces ACCESS_ONCE to work only on scalar types. This is targetted for the next merge window as Linux next already contains new offenders regarding ACCESS_ONCE vs. non-scalar types" * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux: s390/kvm: REPLACE barrier fixup with READ_ONCE arm/spinlock: Replace ACCESS_ONCE with READ_ONCE arm64/spinlock: Replace ACCESS_ONCE READ_ONCE mips/gup: Replace ACCESS_ONCE with READ_ONCE x86/gup: Replace ACCESS_ONCE with READ_ONCE x86/spinlock: Replace ACCESS_ONCE with READ_ONCE mm: replace ACCESS_ONCE with READ_ONCE or barriers kernel: Provide READ_ONCE and ASSIGN_ONCE
Diffstat (limited to 'arch/s390/kvm/gaccess.c')
-rw-r--r--arch/s390/kvm/gaccess.c18
1 files changed, 6 insertions, 12 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 8b9ccf02a2c5..8a1be9017730 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -227,12 +227,10 @@ static void ipte_lock_simple(struct kvm_vcpu *vcpu)
goto out;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
- old = *ic;
- barrier();
+ old = READ_ONCE(*ic);
while (old.k) {
cond_resched();
- old = *ic;
- barrier();
+ old = READ_ONCE(*ic);
}
new = old;
new.k = 1;
@@ -251,8 +249,7 @@ static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
goto out;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
- old = *ic;
- barrier();
+ old = READ_ONCE(*ic);
new = old;
new.k = 0;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
@@ -267,12 +264,10 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu)
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
- old = *ic;
- barrier();
+ old = READ_ONCE(*ic);
while (old.kg) {
cond_resched();
- old = *ic;
- barrier();
+ old = READ_ONCE(*ic);
}
new = old;
new.k = 1;
@@ -286,8 +281,7 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
- old = *ic;
- barrier();
+ old = READ_ONCE(*ic);
new = old;
new.kh--;
if (!new.kh)